1. Field of the Invention
The present invention relates to a magnetic recording/reproducing apparatus having a rotary cylinder.
2. Description of the Related Art
A magnetic recording/reproducing apparatus such as a video tape recorder (VTR) in which signals are recorded on and reproduced from a magnetic tape has conventionally had a rotary cylinder. A magnetic head for recording/reproducing data on and from a magnetic recording medium is placed on the rotary cylinder. The magnetic head includes a head chip having a winding thereon. When the data is to be recorded, a current is made to flow through the winding, thereby generating a magnetic field from a head gap of the head chip. When the data is to be reproduced, the magnetic field in the head gap of the head chip is changed by the magnetic recording medium, thereby making the current flow through the winding.
A unit of the rotary cylinder includes a motor for rotating the magnetic head. A rotor section of the motor has a disk-shaped multipolar permanent magnet (hereinafter, referred to as a "magnet"). The magnet is subject to a magnetic force from a coil of a stator section of the motor, thereby generating a force for rotating the rotor section.
A typical and conventional arrangement of the head gap of the head chip and the magnet will be described, with reference to FIG. 4. A magnetic head includes an head chip 13 having a winding 14. A magnetic field is generated from a head gap 11 of the head chip 13 by making a current flow through the winding 14. The head chip 13 is fixed to a head base 12. The head base 12 is fixed within a rotary cylinder 21 (see FIG. 2) by a fixing screw 15. The rotary cylinder 21 is rotated by the motor, thereby rotating the head gap 11 of the magnetic head.
The magnetic head, as shown in FIG. 4, is positioned above the magnet 10. The arrangement of the head chip 13 and the magnet 10 is fixed by part of the rotary cylinder 21 and remains unchanged during the rotation of the motor.
In the conventional typical rotary cylinder, the head chip 13 is placed so that the head gap 11 is positioned above the polarity boundary area between the S pole and the N pole of the magnet 10. Even in the case where a combination magnetic head in which two head chips are provided for the head base is adopted, the head gaps are placed above the polarity boundary area between the S pole and the N pole.
These days a compact VTR, for example, a compact video camera is made more and more miniaturized. Accordingly, the rotary cylinder should be small in its size. If the rotary cylinder is miniaturized, the magnet 10 for the motor for rotating the rotary cylinder is placed close to the head chip 13. As a result, the leakage of the magnetic field generated from the magnet 10 is likely to magnetize the head chip 13 of the magnetic head. The magnetization of the head chip 13 causes disadvantageous effects such as a lowering of the reproducing output signal level. For example, the magnetic head chip 13 may erase the tracks recorded on the magnetic tape, resulting in a lowering the reproducing outputs (lowering a signal/noise ratio). Therefore, it is required to reduce this effect due to the leakage of the magnetic field from the magnet 10 to become negligible.
The present invention is designed to solve the above problems, and its objective is to provide a magnetic recording/reproducing apparatus in which the effect of the magnetic field leaked from the magnet for the motor on the head chip is greatly reduced.